The present invention discloses a device for mucosal cell and tissue collection, in particular, for an improved device for performing cytological smears and endocervical curettage useful in the detection and diagnosis of cancer, and more particular, an improved device for collecting cytological smears and endocervical tissue for the detection of uterine cervical dysplasia and cancer.
Uterine cervical cancer poses a significant medical risk in the female population. The commonest test for screening a patient for cervical dysplasia or cancer of the cervix consists of obtaining a sample of endocervical and ectocervical cells lining the cervix and performing the Papanicalaou test on the sample, the so called Pap test. A complimentary test, known as the endocervical curettage is used to collect endocervical tissue for pathological analysis.
In its own right, the Pap test is fairly simple to perform and reasonably sensitive in providing accurate and reliable results. A recent advancement has improved the quality of cellular deposit by immersion of samplers into cytology fluid and processing by a monolayer technique. Difficulty persists in achieving an adequate collection and deposition of cells into the cytology fluid for processing and analysis. The traditional method uses a shaped wood spatula, the shaped edge being scraped over the mucosal surface, for example, the mucosa of the ectocervix and opening of the endocervical canal. Unfortunately, this method commonly results in a specimen lacking endocervical cells and occasionally insufficient squamous cells, as well.
Over the years, numerous improvements for cell samplers have been offered. Examples of such improvements include modifying the surface of the wood spatula or making the spatula out of plastic. A sampler with multiple surfaces in concentric rings has been proposed. The most dramatic improvement occurred with the introduction of brushes that provide many small fibers that can be inserted into the endocervix and dragged across the surface of the mucosa. Some physicians are using the latter devices in lieu of performing the traditional endocervical curettage with small metal curettes.
Drawbacks still exist with these devices despite their enhanced surfaces and edges. Inadequate sample cellularity in general, or, more frequently, inadequate endocervical cell/tissue collection or inability of the devices to release the sample into the cytology fluid.
What is needed is a device that is capable of safely and consistently obtaining endocervical glandular cells and or tissue, and ectocervical squamous cells, and readily releasing the cellular collection into cytology fluid.
The present invention is an improved device for obtaining mucosal cell and tissue samples by passing the device of the present invention over the surface of the mucosa. The present invention, as depicted, for example, in FIGS. 1-3, discloses a device having a handle attached to a first plate. The first plate has a first side and a second side and defines a first plane, from which extend a plurality of secondary plates from both a first side and a second side of the first plate. This depicts the symmetry of structure in relation to the first plate that is possible with the present invention. The secondary plates each define planes that are perpendicular to the plane of the first plate and are oriented generally parallel to each other forming a plurality of rows of secondary plates extending from each surface of the first plate. The present invention anticipates that the overall outer shape of the device depends on the overall width of the first plate and height of the secondary plate from the surface of the first plate, the geometry and thickness of the secondary plates, and the shape of the edge of each of the secondary plates. In addition, the secondary plates present surfaces that are parallel to the surface of the next plate. The secondary plates are sufficiently close to be suitable for capillary flow of fluids into and through the interspaces between each secondary plate. Good capillary action can be expected when the inter-space is about one to two millimeters or less. The present invention relies on this capillary action to wick away cell laden fluids from the mucosal surface deep into the interspaces between the secondary plates. The outer edges of the secondary plates may also be contoured with serrations, bevels, or microfilaments at the edges of the secondary plates.
Additional examples of patterns for secondary plates are shown in the various Figures. As depicted in FIG. 5, for example, the present invention discloses a device similar to the embodiments of FIGS. 1-4, but with several tiers of secondary plates. Each secondary plate has a tapered shape. In this embodiment, the taper is roughly two to one in relationship to the distance between the adjacent secondary plates. Other ratios may be used. In addition, the spaces between the secondary plates are even in dimension from proximal to distal. The added advantage of having a tapered secondary plate is to provide variable stiffness to the secondary plates, enhancing the curetting action of the edges of the secondary plates, as well as, enhancing the movement of the cell sample into the spaces between the secondary plates.
The present invention also anticipates that the spaces between the secondary plates may not be parallel, nor may they be so narrow as to provide for capillary action. In addition, these spaces may use geometric shapes and have widths as great as 2 to 4 mm, or larger, and act more as reservoirs for the collected cellular/fluid material as it is scraped free from the mucosal surface.
Another embodiment of the present invention, depicted in FIGS. 6-9, discloses a device having a handle attached to at least two secondary plates. The area of attachment of the secondary plates to the handle serves the function of acting as the first plate. This embodiment serves to depict the asymmetry of structure in relation to the first plate that is possible with the present invention, demonstrating the adaptability of the present invention for use over different mucosal surfaces. The at least two plates are oriented parallel to each other and present a large surface area. The at least two plates are spaced close enough to each other to be suitable for capillary flow of fluids into the space between the at least two plates. In addition, in this embodiment, the at least two plates are spaced apart from each other by a plurality of ribs. The ribs do not extend completely across the breadth of the at least two plates providing for channels between the at least two plates through which air can be displaced to the upper edge of the device as cell laden fluid is drawn into the primary reservoir between the at least two plates along the lower edge of the device.
Both of these embodiments may be attached at opposite ends of the same handle. By way of example, the first embodiment is useful for obtaining glandular cell samples from the lining of the endocervical canal. The second embodiment is useful for obtaining squamous cell samples from the outer surface of the cervix, the ectocervix. When combined on the same handle, the device of the present invention becomes a sampling device useful for obtaining samples of cells from within and without the cervix without having to use multiple devices.
In operation, the handle of the first embodiment is used by an operator to orient the plane of the first plate parallel to the longitudinal axis of the endocervical canal with the planes of each of the secondary plates at right angles to the plane of the first plate, but also parallel to the longitudinal axis of the endocervical canal. The outer profile of the secondary plates, when viewed end on, is circular in cross-section and the plates taper toward the tip at the end of the first plate that is away from the end attached to the handled. When the device is aligned with the endocervical canal, the handle is used to insert the head of the device into the endocervical canal and rotate the head around the axis of the endocervical canal. As the head rotates, cell or tissue samples are collected between the secondary plates and if close enough to each other, held there by capillary action. Alternatively, the cell or tissue samples collect within the reservoir space between the secondary plates. Repeated in and out movement is not necessary, thus diminishing the likelihood of mechanically introducing unwanted contaminants from the vaginal vault into the uterus.
When sampling is completed, the device is withdrawn from the endocervical canal and vaginal vault and the head of the device may be used to either create a smear directly onto a slide or, preferably, dipped into cytology fluid and swished to remove the cells from between the secondary plates or swished in preservative to deposit the tissue. The sample is then ready for the physician, a pathologist, cytologist, or lab technician to prepare for histologic study.
The second embodiment is similarly operated. The handle is used by the operator to align the extended tip of the device with the external os of the cervix. The tip is then placed into the cervical os until the leading edge of the at least two plates contacts the outer surface of the cervical os. The device is then rotated and cell samples are collected between the at least two plates comprising the primary reservoir. The channels provide for release of air pressure as the primary reservoir fills. If needed, the channel spaces may also collect cell sample overflow from the primary reservoir.
When sampling is completed, the device is withdrawn from the vaginal vault and the head of the device is swished into cytology fluid to remove the cell samples from between secondary plates. The channels provide for flow of the cytology fluid through the head of the device between the at least two plates to empty the primary reservoir of cell samples. The sample is then ready for the physician or lab technician to prepare for histologic study.
A number of materials are suitable for use in the various embodiments of the present invention and include, without limitation, synthetic plastics and natural and synthetic rubber compounds. There are a number of plastics known in the art that are useful in this capacity. Examples are poly-vinyl-chloride, polypropylene, polyethylene, polystyrene, polyurethane, polytetrafluoroethylene, and their copolymers. Preferably the plastic is biocompatible, as well as, sterilizable using standard sterilization techniques known in the medical arts. Alternatively, the devices of the present invention may be manufactured in metal or ceramic materials. Useful metals are iron, steel, stainless steel, chromium, tungsten, vanadium, molybdenum, nickel, aluminum, titanium, and alloys of these metals.